This competing renewal for the RMTSC Core on Cellular Visualization and Analysis seeks to continue support services for histology, neuroanatomy and advanced microscopy for RMTSC investigators. This Core offers 3 types of services: 1) training and expertise in specialized histology (e.g. immunocytochemistry) and neuroanatomy, 2) Specialized microscopy facilities and training, including confocal microscopy and digital imaging, and 3) Quantitative analysis and representation of 3D anatomical data. This Core has been highly successful in the past grant period, being involved in experiments from all RMTSC participating laboratories and assisting in most publications arising from the Center. We propose to continue these functions into the next grant period with only minor modifications to the approach and services offered. The principal functions of this Core include provision of training and assistance in the development and application of contemporary histological methods with an emphasis on immunocytochemistry and in situ hybridization. The Core offers quality control and advice in proper utilization of immunological reagents. In addition, the Core provides anatomical expertise to enable investigators from other fields to properly analyze and interpret anatomical images. In terms of microscopy equipment, the Core maintains a RMTSC laser scanning confocal microscope and supports use of other advanced microscopes including spinning disk confocal, 2-photon confocal, Ca-lmaging workstations and transmission electron microscopes. Finally, the Cellular Visualization and Analysis Core offers expertise and development of software capable of rendering 3-D anatomical data in a quantitative enabled format to permit objective measures of changes in activity patterns, endorgan distribution and cellular activity.